1. Field of the Invention
The present invention relates to a plate-link chain composed of a plurality of plates that form plate sets, which are connected to adjacent plate sets with a hinge joint.
2. Description of the Related Art
Plate-link chains are used in transmissions, for example those having continuously variable transmission ratio properties (a continuously variable transmission or CVT). The chain is positioned between pulleys in the form of pairs of conical disks having a variable spacing between the disks of a disk pair, or as a toothed plate-link chain in combination with gears. Chain strand vibrations arise through the effects of forces acting on the chain links as the chain runs onto or off of a sprocket in the toothed plate-link chain transmission, or onto or off a pulley in a CVT transmission. Strand vibrations here mean transverse vibrations of the chain between the pulleys or sprockets. The impacts of the tooth flanks in a toothed plate-link chain in combination with the polygon effect of the link chain excites the chain strand to vibration. A similar thing happens with plate-link chains in CVT transmissions between the rocker member faces and the pulleys. As a result of the entry impulses as the toothed plates enter as a toothed plate-link chain meshes with the gear, vibrations can occur which can reach various frequencies, depending upon the speed of the chain. Such vibrations can have a negative effect on the acoustic behavior of such a chain drive. To prevent those unwanted effects on the acoustic behavior of the transmission, it is possible to install within the transmission additional remedial measures, such as, for example, sliding rails or damping elements. Such measures require additional construction space, however, and also increase the production costs.
Reducing chain strand vibrations by applying measures to the chains is known. For example, U.S. Pat. No. 1,780,040 describes a toothed plate with a right-angle bend on the back. That arrangement blocks the vibration of the chain in one direction. The plate can also be designed as a guide plate. A disadvantage of that solution is the very stiff implementation of the plates, especially in the back region, which results in an increase in the plate rigidity and as a consequence an increase in the tensile stresses at the openings in the plate that receive the hinge pins. An additional disadvantage is the increased construction space required by the chain because of the offset bend, and expensive production costs for the individual plates.
One object of the present invention is to provide plate-link chains that are simple and inexpensive to produce, and that also reduce chain strand vibrations. Another object is to provide a plate-link chain that allows additional damping measures such as sliding rails or damping elements to be dispensed with, so that the requisite construction space and the costs of producing a transmission can be reduced.